Fast and Durable Alkaline Hydrogen Oxidation Reaction at the Electron‐Deficient Ruthenium–Ruthenium Oxide Interface

Abstract The slow hydrogen oxidation reaction (HOR) kinetics under alkaline conditions remain a critical challenge for the practical application of alkaline exchange membrane fuel cells. Herein, Ru/RuO 2 in‐plane heterostructures are designed with abundant active Ru–RuO 2 interface domains as efficient electrocatalysts for the HOR in alkaline media. The experimental and theoretical results demonstrate that interfacial Ru and RuO 2 domains at Ru–RuO 2 interfaces are the optimal H and OH adsorption sites, respectively, endowing the well‐defined Ru(100)/RuO 2 (200) interface as the preferential region for fast alkaline hydrogen electrocatalysis. More importantly, the metallic Ru domains become electron deficient due to the strong interaction with RuO 2 domains and show substantially improved inoxidizability, which is vital to maintain durable HOR electrocatalytic activity. The optimal Ru/RuO 2 heterostructured electrocatalyst exhibits impressive alkaline HOR activity with an exchange current density of 8.86 mA cm −2 and decent durability. The exceptional electrocatalytic performance of Ru/RuO 2 in‐plane heterostructure can be attributed to the robust and multifunctional Ru–RuO 2 interfaces endowed by the unique metal–metal oxide domains.